GlaxoSmithKline’s (NYSE:GSK) former head of operations in China has returned to that country to help investigators with their inquiry into bribery allegations involving GSK executives.

Mark Reilly was the general manager of GSK’s China operations when the company fell under a government inquiry into $490 million that was allegedly used to bribe doctors and officials to boost sales of GSK drugs.

On Tuesday, British newspaper The Telegraph reported that Reilly was being kept in China under a travel ban. But Reuters, citing an unnamed person familiar with the situation, reported that Reilly has has been asked to remain in China during the investigation.

GSK spokesman Mark Steel told The New York Times that Reilly voluntarily returned to China to help Chinese authorities. “At no point was he detained,” Steel told The Times. “Mark remains in China to help further with the investigation should it be required.”

The British Embassy in Beijing also told Reuters that Reilly had not been detained by Chinese authorities.

Police in China in July said that they were investigating whether GSK funneled money to travel agencies as a way of bribing doctors and other officials. GSK replaced Reilly on July 25 after the corruption allegations came to light. Chinese authorities have detained a number of Chinese employees of GSK, including four senior members of GSK’s management team in China. But Reuters reports that the authorities have not detained any foreign nationals who work for GSK.

GSK has said that the allegations involve individuals who work at the company and that bribery is not supported by the company. Since the GSK investigation became public, Chinese officials have also looked into the operations of other drug companies that operate in China, including Sanofi, Novartis, AstraZeneca, Eli Lilly and Bayer. Reuters reported that analysts at Deutsche Bank said that the anti-bribery campaign was likely to last for some time, impacting both multinational and domestic drug companies.

London-based GSK operates its U.S. headquarters in Research Triangle Park.